Design of Fuzzy Feed-forward Decoupling System based on FPGA

Abstract

Coupling is a common phenomenon in process control system, which will decrease the performance of control systems. And what's worse, if the coupling is serious, the system can not work[1]. Therefore, it is significant to research decoupling in the fields of control theory and project practice. Nowadays, decoupling is always implemented by software. However, this method canpsilat satisfy the controlled plant for high speed because of bad real-time effect. Conversely, adopting the hardware decoupling could control the objects timely. There are many ways to realize decoupling by hardware, FPGA is an ideal method. FPGA is a kind of field programmable logical component, which adopts the EDA technology and uses hardware describing language as an expression of logic. It has many traits, such as shorter developing periods, higher speed, upgradeable online, and is suitable for teamwork. A kind of fuzzy feed-forward decoupling algorithm based on error[2] is applied in this paper. On one hand, with adopting fuzzy control, the algorithm does not rely on a mathematic model, and is able close to non-linearity. On the other hand, the speed of algorithm based on error is faster than the decoupling arithmetic based on output.Based on the analyses of a lot of coupling phenomenons, a kind of fuzzy feed-forward decoupling controller based on FPGA is designed in this paper. As a carrier with FPGA, the controller has smaller size, higher reliability, lower consumption and so on. With adopting the method of converting software idea to hardware circuit, the controller could improve the response speed. This paper chooses different plants as researching objects in the course of simulation and practice. According to the experimental results, the decoupling effect of the controller is obvious, which provides a feasible way for the development of the decoupling technology.